Thursday, 26 July 2012 15:36

Anamorphic vs. Non-Anamorphic DVD (2.35:1 Aspect Ratio Film)

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The following is a comparison of anamorphic and non-anamorphic (letterboxed) widescreen DVD video, as displayed on Standard 4x3 and Digital 16x9 TVs. For this demonstration, we've chosen to use snapshots of actual DVD video from the film Rushmore (aspect ratio is 2.35:1). Buena Vista's original DVD version (on the left) is non-anamorphic. By contrast, The Criterion Collection DVD release (on the right) is anamorphic.

Non-Anamorphic (Letterboxed) Anamorphic

The video recorded on a non-anamorphic DVD.

The video recorded on an anamorphic DVD.
The video recorded on a non-anamorphic DVD. Notice that the black bars at the top and bottom of the frame are somewhat thicker than in a 1.85:1 presentation. Since the 2.35:1 aspect ratio is wider, the thicker bars are necessary to maintain the proper composition. These are actually present in the signal.

The video recorded on an anamorphic DVD. Notice that the image appears "squished" horizontally, while retaining nearly its full vertical resolution. In addition, black bars are now visible at the top and bottom of the frame. Since the 2.35:1 aspect ratio is wider, the bars are necessary to maintain the proper composition. These are actually present in the signal. Normally, you would never see the video in this state. The only time you would see this "squished" picture, is if you were watching the disc on an improperly set-up DVD player, using a Standard 4x3 TV - the player thinks you have a Digital 16x9 TV. A quick adjustment in the player's menu would correct this problem.

Non-anamorphic video as it appears on a Standard 4x3 TV. Anamorphic video as it appears on a Standard 4x3 TV.
Non-anamorphic video as it appears on a Standard 4x3 TV. This is the familiar letterboxed image you're used to.

Anamorphic video as it appears on a Standard 4x3 TV. The DVD player performs a mathematical downconversion on the video signal, in effect combining every 4 lines of vertical resolution into 3 until the correct aspect ratio is achieved. Electronically-generated black bars are added to the existing ones (to fill in the remaining screen area), completing the image. Visually, it's nearly indistinguishable from a non-anamorphic (letterboxed) DVD image.

Non-anamorphic video as it appears on a Digital 16x9 TV. Anamorphic video as it appears on a Digital 16x9 TV.
Non-anamorphic video as it appears on a Digital 16x9 TV. The gray bars are generated by the TV to fill in the remaining screen area. Using the TV's "zoom" mode, you can magnify the image to fill the screen electronically, but at the cost of degrading the image quality significantly.

Anamorphic video as it appears on a Digital 16x9 TV. The "squished" image recorded on the disc (seen at top) is sent directly to the TV, which stretches the video signal horizontally until the correct aspect ratio is achieved. As you can see, the image fills the frame, while retaining nearly its full vertical resolution. Since the 2.35:1 aspect ratio is wider, thin black bars are still necessary to maintain the proper composition (they're in the video signal). The picture quality is stunning.